Stimulating the differentiation of predipocytic cells and therapies based thereon

ABSTRACT

The differentiation of preadipocytic cells into adipocytic cells, in particular for correcting insulin-resistance disease states in mammalian organisms, notably in humans, for example type II diabetes and cardiovascular disorders such as hypertension and atherosclerosis, is stimulated by treating such preadipocytic cells, or a patient in need of such treatment, with an effective amount of (a) at least one ligand displaying affinity for the nuclear receptors for retinoic acid and/or isomers thereof, preferably at least one ligand displaying a specific affinity for the RAR receptors and even more preferably the RAR-α receptor and (b) at least one fatty acid, e.g., a polyunsaturated fatty acid.

This application is a divisional of application Ser. No. 08/510,312,filed Aug. 2, 1995, U.S. Pat. No. 5,728,739.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The present invention relates to novel pharmaceutical compositions forapplications in human or veterinary medicine, intended more especiallyfor accelerating in vitro and/or in vivo the differentiation ofpreadipocytic cells into adipocytic cells, and to the use of such novelcompositions for correcting an insulin-resistance state existing in aliving mammal, and thus of treating and/or preventing in, e.g., humans,the different physiopathologies which may be associated with such adisease state.

2. Description of the Prior Art

Certain skin cells deemed adipocytes are known to contain variableamounts of fats in the form of triglycerides. These triglycerides aresynthesized in vivo actually within the adipocytes via enzymatic typereactions (lipogenesis), from free fatty acids and glucose (afterdegradation of the latter to glycerophosphate) in circulation in thebody and supplied thereto by certain foods. In parallel, thetriglycerides thus formed and then stored in the adipocyte cells mayalso again break down, once more under the influence of specific enzymes(lipolysis) contained in these same cells, in this instance liberatingfree fatty acids on the one hand and glycerol and/or glycerol mono-and/or diesters on the other. The fatty acids thus released may theneither diffuse in the body and be consumed or converted via differentmechanisms therein, or be taken up again (at once or a short time later)by the adipocytes to again generate triglycerides by lipogenesis.

The adipocytes present in the adipose tissue themselves originate inknown manner from the transformation of precursor stem cells, designatedpreadipocytes, which are cells of fibroplastic appearance capable ofmultiplying and differentiating into adipocytes under the influence ofcertain hormonal agents such as, for example, insulin or growth hormone.

In humans, the amount of preadipocytes which can be isolated from theadipose tissue and which are capable of subsequently differentiatinginto adipocytes is inversely proportional to the individual's age;however, even in elderly individuals, there always remains a proportionof so-called "dormant" cells capable of being reactivated at a laterpoint in time. Stated differently, throughout its life, the adiposetissue contains preadipocytes capable of differentiating into adipocytesunder the influence of various appropriate stimuli. In this respect, itis known to this art that free fatty acids on the one hand, as well as,on the other, natural retinoids, when the latter are administered atphysiological concentrations (1-10 nM), and synthetic retinoids whenthey are administered at very low concentrations (1 pM-1 nM)individually, good stimulators of preadipocyte differentiation.

It too is known to this art that insulin (which is a natural proteinhormone produced in variable amounts by certain cells of the pancreas,known as β cells) also participates substantially, or even essentially,in the process of lipogenesis indicated above. In effect, one of thelimiting parameters in the utilization by the adipocytes of theextracellular glucose contained in the body for the purpose of itsultimate conversion into triglycerides is the prior uptake, transportand diffusion of this glucose through the plasma membrane of theadipocyte cell; only glucose which has successfully permeated throughthis plasma membrane will be converted to glycerophosphate and then totriglycerides. It is now known that this transport of glucose iseffected by particular and fully identified glycoproteins which arelocated at the outer surface of the plasma membrane, and which aretermed for simplicity "glucose transporters" or "GLUT". In point offact, it is the case that certain of these GLUT (termedinsulin-sensitive transporters or GLUT-4) consist, in addition, ofprotein receptors specific for insulin, to which (normally) the lattercan become bound very firmly (creation of protein complexes of theinsulin-insulin receptor type). One of the major effects of insulinbeing bound in this manner to these specific receptors is to produce,according to complex but known mechanisms of activation which need notbe here elucidated, a significant increase in the number of GLUT at thesurface of the adipocyte, thereby generating a significant increase inthe amounts of glucose transported through the plasma membrane, andhence, as a result, in the amounts of triglycerides produced inside theadipocyte. In this regard, it is known that marked defects in a livingorganism in respect of insulin production, or, alternatively, in respectof the functioning of the insulin receptors, are responsible for variousmore or less serious pathologies, and in particular for a disease statereferred to as sugar diabetes, more fully discussed below.

If, for various reasons (excessively rich food, inactivity, aging andthe like), a substantial metabolic imbalance establishes itself in thebody between the synthesis of lipids (formation of triglycerides byenzymatic reaction between fatty acids and glycerophosphate originatingfrom glucose) and their degradation by lipolysis (enzymaticdecomposition of triglycerides to fatty acids and glycerol), or, moreprecisely, if the amounts of fats formed by lipogenesis (the "inputs")become significantly and consistently greater than those which areremoved by lipolysis (the "outputs"), an accumulation of triglyceridesthen occurs in the adipocytes. If this becomes excessive, it canmanifest itself gradually in the appearance of a thick skin with asurface which is often irregular ("orange peel") and of more or lessflabby or gelatinous consistency, finally resulting in the body having agenerally unsightly appearance which can progress from simple localoverweight (lipodysmorphism) through definite stoutness and ultimatelyto true obesity.

Obesity corresponds to a pathological state which is characterized by ageneralized and substantial hypertrophy of the adipose tissue,associated with an excessive increase in both the number, the mass andthe volume of the adipocytes and originating from the metabolicimbalance described above. In view of the profound discomfort, bothphysical and aesthetic and ofttimes psychological, it causes in theindividuals who are affected, obesity is today a condition which isbeing less and less well endured or accepted. Furthermore andunfortunately, obesity is also often accompanied by more or less serioussecondary metabolic disorders. Thus, it too is known, in particular,that obesity strongly predisposes to the early onset of certain types ofsugar diabetes. Sugar diabetes, which is the sixth most common fataldisease in the United States, is defined, in general, as a pathologicalstate of blood hyperglycemia, and, at present, two principal types ofsugar diabetes are distinguishable precisely, according to the origin ofthis excess glucose in the blood: so-called insulin-dependent diabetes(or IDD), also termed type I diabetes, and non-insulin-dependentdiabetes (or NIDD), also termed type II diabetes. As indicated above,insulin is a natural regulator of the blood glucose concentration. Adeficit or ceasing of insulin production in the body causes type Idiabetes; individuals suffering from such a disease state must regularlybe treated by supplementary injections of insulin. The other casecorresponds to that where insulin, though present in apparently normalamounts in the body, is inactive or insufficiently active with respectto glucose, as a result of certain deficiencies regarding the functionswhich should be exerted by the insulin receptors; the state of the bodyis then qualified as insulin-resistant, and must be treated withspecific antidiabetic agents.

Thiazolidinediones and derivatives thereof, and especially that havingthe formula: ##STR1## are especially valuable antidiabetic agents,recognized as enabling the state of resistance which a body may exhibitto the action of insulin to be corrected in vitro and in vivo, anduseful for simultaneously stimulating the process of differentiation ofpreadipocytes into adipocytes.

Nonetheless, and unfortunately, one of the drawbacks of this type ofcompound is that, at the doses at which they are typically administered,they elicit more or less substantial undesirable side effects.

SUMMARY OF THE INVENTION

It has now unexpectedly been determined that a very substantial synergyof activity exists between certain judiciously selected compounds foractivating and stimulating, markedly improvedly, the differentiation ofpreadipocytes into adipocytes.

Briefly, the present invention features novel pharmaceuticalcompositions comprising (a) a compound (or ligand) displaying anaffinity for the nuclear receptors for retinoic acid and/or the isomersthereof (namely, the RAR and RXR receptors) and (b) a fatty acid, whichnovel compositions stimulate preadipocyte differentiation quiteexceptionally.

BRIEF DESCRIPTION OF THE DRAWING

The Figure of Drawing is a bar graph plotting the level ofdifferentiated preadipocytes as a function of the particular activeagents employed, as well as the concentrations thereof.

DETAILED DESCRIPTION OF BEST MODE AND PREFERRED EMBODIMENTS OF THEINVENTION

More particularly according to the present invention, optimumsynergistic results are attained using compositions which comprise,preferably, a ligand specific for the RAR receptors (relative to the RXRreceptors), even more preferably, a ligand specific for RARs which is,in addition, selective with respect to one or two (but preferably onlyone) subtypes (RAR-α, RAR-β, RAR-γ) of these RARs, and, lastly, mostpreferably, a ligand specific for RARs which is, in addition, selectivewith respect to the RAR-α receptor.

Thus, the present invention features novel compositions of matter, inparticular medicinal or pharmaceutical compositions, comprising, in avehicle, carrier or diluent which is physiologically/pharmaceuticallyacceptable and especially compatible with the intended mode ofadministration thereof, (a) at least one ligand displaying an affinityfor the nuclear receptors for retinoic acid and/or isomers thereof,preferably a ligand specific for the RAR receptors and even morepreferably a ligand selective for the RAR-α receptor, and (b) at leastone fatty acid. The two compounds (a) and (b) can be combined physicallyin the composition (intimate admixture), or, to the contrary, can bepresent separately in different discrete compartments of appropriatepackaging or dosage form (composition in the form of "kits").

The present invention thus also features multi-compartment packaging or"kits" which comprise, in a first compartment, one or more ligandsdisplaying an affinity for the nuclear receptors for retinoic acidand/or isomers thereof, preferably a ligand specific for the RARreceptors and even more preferably a ligand selective for the RAR-αreceptor, and, in a second compartment, one or more fatty acids. Theactive species contained in the first and second compartments areconsidered to be combination compositions for administrationsimultaneously, separately or staggered over time in a therapeutictechnique for promoting and/or stimulating the differentiation ofpreadipocytes into adipocytes.

The subject compositions and/or kits for stimulating the differentiationof preadipocytes into adipocytes are particularly useful for thetreatment of insulin-resistance states and/or associatedphysiopathologies.

Hence, this invention also features a therapeutic regime or regimen forstimulating the differentiation of preadipocytes into adipocytes, inparticular for the treatment of insulin-resistance disease states and/orphysiopathologies associated with such disease states, comprisingadministering to an organism in need of such treatment, preferablysystemically, a therapeutically effective amount of at least one liganddisplaying an affinity for the nuclear receptors for retinoic acidand/or isomers thereof, preferably a ligand specific for the RARreceptors and even more preferably a ligand selective with respect tothe RAR-α receptor, and a therapeutically effective amount of at leastone fatty acid. These different compounds can be administeredsimultaneously, separately or, alternatively, staggered over time.Preferably, they are administered simultaneously.

The compositions of the invention may of course be introduced directlyinto suitable cell cultures of preadipocytes (in vitro application).

In general, the unit dose amounts of active agents employed, incombination, to elicit the desired primary therapeutic effect alwaysremain very low (synergy), which presents a considerable advantage inrespect of problems of tolerance or of undesirable side effects in theorganisms treated, or over the course of treatment.

In light of the exceptional activities they display with respect to thedifferentiation of preadipocytic cells, the compositions according tothe invention are very well suited for applications in the curativeand/or prophylactic treatment of patients affected by insulin resistanceor by all other physiopathologies associated with this disease state.Such physiopathologies are, in particular, type II diabetes, as well ascardiovascular diseases such as, for example, hypertension andatherosclerosis. The insulin-resistance disease state in a patient maybe detected conventionally via the glucose tolerance test, and thetreatment according to the invention may be initiated as soon as thistest proves positive, even before any clinical manifestation of an onsetof disease (preventive treatment).

The various active agents according to the present invention will now bemore fully described.

Specific ligands (or Retinoids)

Retinoic acid, which is a natural metabolite of vitamin A (retinol), isknown to this art as a potent modulator (i.e., an inhibitor or, to thecontrary, a stimulator, depending on the nature of the cells treated) ofthe differentiation and proliferation of many normal or transformed celltypes.

all-trans-Retinoic acid acts on the differentiation and proliferation ofcells by interacting with nuclear receptors or RARs (retinoic acidreceptors) contained in the cell nucleus. There are, to date, threeidentified subtypes of known RAR receptors, respectively termed RAR-α,RAR-β and RAR-γ. These receptors, after binding the ligand (i.e.,retinoic acid), interact with the promoter region of genes regulated byretinoic acid at specific response elements. To bind to the responseelements, the RARs heterodimerize with another type of receptordesignated as RXR. The natural ligand of RXRs is 9-cis-retinoic acid.

Many synthetic structural analogs of retinoic acid or of 9-cis-retinoicacid, typically designated "retinoids", have, moreover, been describedto date in the literature. Certain of these molecules are capable ofbinding and specifically activating RARs or, to the contrary, RXRs.Furthermore, certain analogs can bind and activate one particularsubtype of RAR receptor (α, β or γ). Lastly, other analogs do notdisplay any particular selective activity with respect to thesedifferent receptors. In this respect, and for example, 9-cis-retinoicacid activates both RARs and RXRs, without significant selectivity forone or the other of these receptors (nonspecific ligand), whereasall-trans-retinoic acid, in its turn, specifically activates RARs(RAR-specific ligand) without discrimination between subtypes. For thepurposes of the present invention, and qualitatively, a given compoundor substance (or ligand) is termed selective or specific with respect toa given family of receptors (or, respectively, with respect to aparticular receptor of this family) when said substance displays astrong or very strong affinity for all of the receptors of this family(or, respectively, for the particular receptor of this family) and whenit displays, moreover, a low or very low affinity for all of thereceptors of any other family (or, respectively, for all otherreceptors, of this same family or otherwise).

Quantitatively, such affinity is measured by means of classical bindingtechniques (Kd values) and, according to the present invention, anycompound which, with regard to a given first receptor, possesses a Kd atleast 5-fold less, and preferably at least 10-fold less, than the Kd itpossesses with regard to a given second receptor may be qualified as aspecies which is selective with respect to this first receptor relativeto this second receptor; it is qualified as specific when the ratiobetween the said Kd values is at least 100. The evaluation of theselective or nonselective, or specific or nonspecific, character ornature of a given compound with regard to a given receptor istraditionally conducted by means of in vitro tests well known to thisart (see, in particular: (1) "Selective Synthetic Ligands for NuclearRetinoic Acid Receptor Subtypes," in RETINOIDS, Progress in Research andClinical Applications, Chapter 19 (pp. 261-267). Marcel Dekker Inc,edited by Maria A. Livrea and Lester Packer; (2) "Synthetic Retinoids:Receptor Selectivity and Biological Activity" in Pharmacol Skin, Basel,Karger, 1993, Volume 5, pp. 117-127; (3) "Selective Synthetic Ligandsfor Human Nuclear Retinoic Acid Receptors," in Skin Pharmacology, 1992,Vol. 5, pp. 57-65; (4) "Identification of Synthetic Retinoids withSelectivity for Human Nuclear Retinoic Acid Receptor-γ," in Biochemicaland Biophysical Research Communications, Vol. 186, No. 2, July 1992, pp.977-983; (5) International Patent Application WO 93/21,146).

According to the present invention, of the above (natural or synthetic)retinoids, only those which display a specific affinity for the RARreceptors, i.e., ligands displaying a greater affinity for the latterreceptors than for the RXR receptors, are the preferred.

In another preferred embodiment of the present invention, theRAR-specific retinoids are selected from among those which display, inaddition, a selective affinity for at least one of the receptors RAR-α,RAR-β and RAR-γ, and preferably the RAR-α receptor.

It is of course possible to employ one or more ligands displaying anaffinity for the nuclear receptors for retinoic acid and/or isomersthereof, or one or more ligands displaying a specific affinity withrespect to the RAR receptors, or one or more ligands displaying aselective affinity with respect to the RAR-α receptor, or,alternatively, combinations from among these different ligands.

Particularly exemplary retinoids which are both RAR-specific andRAR-α-selective in accordance with this invention include 4-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl)carboxamido!benzoicacid and 4-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl)carbamoyl!benzoicacid.

Particularly exemplary retinoids specific for RAR includeall-trans-retinoic acid,4-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-anthracenyl)benzoic acid, 4-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl)carboxamido!benzoicacid, 6- 3-(1-adamantyl)-4-hydroxyphenyl!-2-naphthoic acid, 6-3-(1-methylcyclohexyl)-4-methoxyphenyl!-2-naphthoic acid and adapalene.

Fatty acids

The fatty acids which are suitable according to the present inventioncan be saturated or, to the contrary, unsaturated fatty acids. Among thelatter, preferred are the polyunsaturated fatty acids, and especiallypolyunsaturated C₁₈ -C₂₂ fatty acids (including the so-called"essential" fatty acids), and in particular the C₂₀ acids. The subjectfatty acids, in addition, can also be metabolizable ornon-metabolizable. Fatty acid precursors can also be employed, namely,compounds which are metabolized in vivo by the body into fatty acids,or, alternatively, compounds which induce the formation ofpolyunsaturated fatty acids in living tissue. This can be establishedobjectively by gas chromatography or by any other standard techniquesuch as those described by Pelick et al. P23 "Analysis of lipids andlipoproteins", Perkins American Oil Chemist Society editions, ChampaignIll. U.S.A.

Exemplary fatty acids which are particularly well suited according tothe present invention include arachidonic acid, dihomo-gamma-linolenicacid, eicosapentaenoic acid, docosahexaenoic acid and oleic, linoleic,α-linolenic and γ-linolenic acids, as well as palmitic and, especially,α-bromopalmitic acid.

In a preferred embodiment of the invention, the fatty acids are selectedfrom among the ω₃ and ω₆ type polyunsaturated fatty acids. Particularlypreferred such fatty acids are α-linolenic acid and arachidonic acid.

The above indicated fatty acids (or precursors thereof) may be obtained,in particular, from certain natural materials, especially from certainfoods of animal, vegetable or microbial origin (extracts of vegetableoils such as Oenothera biennis oil, borage oil, blackcurrant-pip oil,evening primrose oil, fish oil extracts and extracts of insect tissueoils). According to the invention, it is of course also intended todirectly use such natural materials which contain the desired fattyacids or fatty acid precursors. It is also possible to use syntheticproducts. Lastly, it will also be appreciated that it is obviouslyintended to employ mixtures of fatty acids.

In general, the retinoids and the fatty acids in accordance with thepresent invention may be packaged conventionally in a form suited to themode of administration or application ultimately selected for thesecompounds. The compositions according to the invention may thus beadministered enterally, parenterally or, alternatively, transcutaneouslyor transdermally (with or without the use of penetration promoter(s)).However, preferably, the subject compositions are formulated in a formsuitable for enteral application.

The preferred compositions according to the present invention arepharmaceutical compositions comprising, in aphysiologically/pharmaceutically acceptable vehicle, carrier or diluent,at least one retinoid specific for the RAR receptors, and which is morepreferably, in addition, selective for the RAR-α receptor, as a firstactive principle, in intimate admixture with at least one fatty acidpresent as a second active principle. These compositions are preferablyformulated and packaged in a form suitable for systemic administrationand, even more preferably, for oral administration. This is also thecase in respect of the "kits" according to the invention; in particular,the compositions included in each of the compartments of the kit arepreferably formulated in a form suitable for systemic, advantageouslyoral administration. It should also be appreciated that kits can bedesigned containing the same number of separate compartments as activespecies (retinoids, fatty acids) in the intended final composition.

For enteral administration, the medicinal/pharmaceutical compositions ofthe invention can be formulated as tablets, hard gelatin capsules,dragees, syrups, suspensions, solutions, powders, granules, emulsions,microspheres or nanospheres, or lipid or polymeric vesicles permitting acontrolled release thereof.

For parental administration, the subject medicinal/pharmaceuticalcompositions can be formulated as solutions or suspensions for perfusionor for injection.

The compositions according to the invention, or the kits comprisingsame, can also include any of the various excipients and othertraditional additives and adjuvants which are typically employed in thepharmacopoeia or pharmaceutical arts (colorants, texturizing agents,perfumes, fragrances, preservatives and the like).

The amounts of the specific retinoid(s) employed according to thepresent invention are not strictly critical, and can thus vary overfairly wide limits. In the instance of preparations intended forsystemic administration, the dose amounts must remain compatible withthe traditional requirements associated with the toxicology andformulation of pharmaceuticals; in this respect, administration dosesranging from 0.005 mg/kg/day to 5 mg/kg/day are generally suitable.

Similarly, the amounts of fatty acid(s) to be administered generallyrange from 1 mg/kg/day to 50 mg/kg/day.

To elicit significant therapeutic effects, the frequencies or regimen ofadministration of the compositions according to the invention, which areof course dependent on the amounts of active agents employed at eachapplication, are on the order of once to twice daily. The therapy isthen continued regularly for several days and, preferably, for severalweeks or even several months.

In order to further illustrate the present invention and the advantagesthereof, the following specific examples are given, it being understoodthat same are intended only as illustrative and in nowise limitative.

EXAMPLE 1

This example demonstrates the in vitro activity of the synergisticimmixtures according to the invention with respect to thedifferentiation of preadipocytic cells into adipocytic cells.

The compounds tested were the following:

Retinoids

R1: 4-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-anthracenyl)benzoic acid(RAR-specific retinoid, without particular selectivity for α, β or γsubtypes);

R2: 4-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl)carboxamido!benzoicacid (RAR-specific retinoid selective for RAR-α);

R3: 6- 3-(1-methylcyclohexyl)-4-methoxyphenyl!-2-naphthoic acid(RAR-specific and RAR-β- or -selective retinoid);

R4: 6- 3-(1-adamantyl)-4-hydroxyphenyl!-2-naphthoic acid (RAR-specificand RAR-γ-selective retinoid);

R5: 9-cis-retinoic acid (nonspecific retinoid).

Fatty acid

α-Bromopalmitic acid.

The preadipocytic cells used were cells originating from the lineOb1771.

The experimental protocol and the methods of determination of thedifferentiation activities were as follows:

Cell culture

Cells were cultured at 37° C. in a humid atmosphere in the presence of5% of CO₂ in DME medium (Gibco) with the addition of antibiotics(penicillin 100 U/ml and streptomycin 50 mg/ml) and 8% (v/v) of fetalcalf serum (FCS) (standard medium).

Treatment of cells

Ob1771 cells were inoculated in the proportion of 2×10⁴ cells in 2 ml ofstandard medium with the addition of 17 mM insulin, 2 nMtriiodothyronine, 100 μM putrescine and 10 μM methylglyoxalbis(guanylhydrazone) in 10 cm² cluster wells. The cells were treatedimmediately after inoculation with the retinoids indicated above and/orα-bromopalmitic acid, both diluted in ethanol. The final ethanolconcentration did not exceed 0.1% (v/v). After 8 days of culture, thecells were harvested for the determination of differentiation.

Measurement of differentiation

Differentiation was determined by means of the glycerophosphatedehydrogenase (GPDH) activity measured spectrophotometrically at 340 nm.It is expressed in mU (μmol/min)/mg of protein. The stronger theactivity, the higher the proportion of differentiated cells. The resultsare expressed relative to the activity determined in cells not exposedto the retinoids and/or the fatty acid (35±5 mU/mg).

All of the results obtained are reported in the Figure of Drawing. ThisFigure quantifies the changes in the level of differentiatedpreadipocytes as a function of the active agents used, on the one hand,and of their concentration on the other (R1: 10⁻³ nM; R2: 10⁻² nM; R3: 1nM; R4: 1 nM; R5: 1 nM). In all cases, the concentration of fatty acid(when present) was fixed at 5 μM; (+) indicates the presence of thisfatty acid and (-) its absence. The values given at the control pointcorrespond to the results found when no retinoid was employed (in thelatter case, (-) corresponds to the values found when no active agentwas employed (absence of fatty acid) and (+) to those found on employingonly the fatty acid at a concentration of 5 μM).

These results clearly demonstrate the synergistic effects elicited byuse of the combinations according to the invention, the amount ofdifferentiated cells being, in effect, consistently greater than thesimple arithmetic sum of the amounts of differentiated cells obtainedwhen the retinoids and the fatty acid were employed separately and inisolation.

EXAMPLE 2

Three specific formulations according to the invention, and which are ina form suitable for oral administration, are set forth in this example.

(a) 1 g capsule containing 0.5 g of an oily suspension comprising:

    ______________________________________                                        (i)       Compound R1 of Example 1                                                                       0.25 mg                                            (ii)      α-Linoleic acid                                                                          250 mg                                             (iii)     Liquid paraffin qs                                                                             500 mg                                             ______________________________________                                    

The shell of the capsule was manufactured according to a conventionaltechnique of molding and then drying a suitable mixture comprising:gelatin, glycerol, water and preservative. The operations of mixing andthen of withdrawing the ingredients constituting the oily suspensionwere carried out under an inert gas.

(b) 0.30 ml hard gelatin capsule (opaque M^(o) 3 calibrated standardshell) containing:

    ______________________________________                                        (i)      Adapalene             5     mg                                       (ii)     α-Bromopalmitic acid                                                                          50    mg                                       (iii)    Silica ("AEROSIL 200" marketed                                                                      50    mg                                                by Degussa)                                                          (iv)     Lactose qs            0.3   ml                                       ______________________________________                                    

(c) 0.5 g insoluble tablet comprising:

    ______________________________________                                        (i)       Compound R2 of Example 1                                                                       2.5 mg                                             (ii)      α-Bromopalmitic acid                                                                     100 mg                                             (iii)     Lactose          85 mg                                              (iv)      Purified talc    15 mg                                              (v)       Sweetener qs                                                        (vi)      Colorant qs                                                         (vii)     Starch qs        500 mg                                             ______________________________________                                    

While the invention has been described in terms of various preferredembodiments, the skilled artisan will appreciate that variousmodifications, substitutions, omissions, and changes may be made withoutdeparting from the spirit thereof. Accordingly, it is intended that thescope of the present invention be limited solely by the scope of thefollowing claims, including equivalents thereof.

What is claimed is:
 1. A regimen for treating an insulin-resistant statein a mammalian organism in need of such treatment, comprisingadministering to such organism a therapeutically effective amount of (a)at least one ligand displaying affinity for the nuclear receptors forretinoic acid and/or isomers thereof, and (b) at least one fatty acid.2. The regimen as defined by claim 1, for the treatment of type IIdiabetes.
 3. A The regimen as defined by claim 1, for the treatment of acardiovascular disease state.
 4. The regimen as defined by claim 1,comprising simultaneously administering said at least one ligand (a) andsaid at least one fatty acid (b).
 5. The regimen as defined by claim 1,comprising separately administering said at least one ligand (a) andsaid at least one fatty acid (b).
 6. The regimen as defined by claim 1,comprising staggeredly administering said at least one ligand (a) andsaid at least one fatty acid, over time.
 7. A regimen for treating aninsulin-resistant state in a mammalian organism in need of suchtreatment, comprising administering to such organism a therapeuticallyeffective amount of a composition of matter suited for thedifferentiation of preadipocytic cells into adipocytic cells comprising(a) at least one ligand displaying affinity for the nuclear receptorsfor retinoic acid and/or isomers thereof, and (b) at least one fattyacid.
 8. The regimen of claim 1, said at least one ligand (a) comprisinga ligand displaying a selective affinity for the RAR receptors.
 9. Theregimen as defined by claim 8, said at least one RAR-specific ligand (a)not displaying selective affinity for one of the subtypes of RARreceptors.
 10. The regimen as defined by claim 8, said at least oneligand (a) displaying a selective affinity for the RAR receptors alsodisplaying a selective affinity for at least one of the subtypes of RARreceptors.
 11. The regimen as defined by claim 8, said at least one ofthe subtypes of RAR receptors comprising the RAR-α receptor.
 12. Theregimen as defined by claim 1, said at least one ligand (a) beingselected from the group consisting of 4-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl)carboxamido!benzoicacid, 4-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl)carbamoyl!benzoicacid, all-trans-retinoic acid,4-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-anthracenyl)benzoic acid, 4-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl)carboxamido!benzoicacid, 6- 3-(1-adamantyl)-4-hydroxyphenyl!-2-naphthoic acid, 6-3-(1-methylcyclohexyl)-4-methoxyphenyl!-2-naphthoic acid and adapalene.13. The regimen as defined by claim 1, said at least one fatty acid (b)comprising a saturated or unsaturated fatty acid.
 14. The regimen asdefined by claim 13, said at least one fatty acid (b) comprising apolyunsaturated fatty acid.
 15. The regimen as defined by claim 14, saidpolyunsaturated fatty acid having from 18 to 22 carbon atoms.
 16. Theregimen as defined by claims 14, said polyunsaturated fatty acid beingof W₃ or W₆ type.
 17. The regimen as defined by claim 1, said at leastone fatty acid (b) being selected from the group consisting ofarachidonic acid, dihomo-gamma-linolenic acid, eicosapentaenoic acid,docosahexaenoic acid, oleic acid, linoleic acid, α-linolenic acid,γ-linolenic acid, palmitic acid and α-bromopalmitic acid.
 18. Theregimen as defined by claim 7, wherein said at last one ligand (a) isselected from the group consisting of 4-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl)carboxamido!benzoicacid, 4-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl)carbamoyl!benzoicacid, all-trans-retinoic acid,4-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-anthracenyl)benzoic acid, 4-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl)carboxamido!benzoicacid, 6- 3-(1-adamantyl)-4-hydroxyphenyl!-2-naphthoic acid, 6-3-(1-methylcyclohexyl)-4-methoxyphenyl!-2-naphthoic acid and adapalene.19. The regimen as defined by claim 7, wherein said at least one fattyacid (b) comprises a saturated or unsaturated fatty acid.
 20. Theregimen as defined by claim 19, said at least one fatty acid (b)comprising a polyunsaturated fatty acid.
 21. The regimen as defined byclaim 20, said polyunsaturated fatty acid having from 18 to 22 carbonatoms.
 22. The regimen as defined by claim 20, said polyunsaturatedfatty acid being of W₃ or W₆ type.
 23. The regimen as defined by claims7, said at least one fatty acid (b) being selected from the groupconsisting of arachidonic acid, dihomo-gamma-linolenic acid,eicosapentaenoic acid, docosahexaenoic acid, oleic acid, linoleic acid,α-linolenic acid, γ-linolenic acid, palmitic acid or a-bromopalmiticacid.